Hominin Tool Evolution and Its (Surprising) Relation to Language Origins

Abstract

Culture and communication are widespread in the animal kingdom. However, among apes, only the human line has evolved these into something altogether different. Moreover, our extraordinary cultural and communicative capacities underlie much else of what makes our species stand out among apes. Thus, understanding the how and why of the process by which these capacities were transformed from their great ape-like precursors into their modern human equivalents is of fundamental importance to the challenge of understanding the evolution of our species more generally. In this chapter, we take up these questions using a novel framework for thinking about social learning. We hypothesize that human apes show a unique propensity for a certain type of social learning, which we call “know-how copying.” Know-how copying is considered foundational to our species’ well-known capacity to culturally evolve both behaviour and artifact forms that can far exceed anything a single individual could realistically invent on his or her own. This copying is therefore also foundational to our species’ capacity to construct, maintain and expand the large lexicons of (often) arbitrary signs that underlie human languages. After discussing the various methodologies that are available for testing whether a given type of human or animal culture is demanding of know-how copying, we turn to the archaeological record with an eye towards identifying plausible signatures of the origins of know-how copying in the human line. In particular, we examine the course of hominin technological evolution – as the most visible and most frequent data. We suggest a much later date for the origins of know-how copying than is typically assumed. But this poses a deep puzzle, namely: there is good reason to think that hominins had considerably expanded their communicative repertoire prior to the evolution of know-how copying. How was this possible in the seeming absence of know-how copying? We sketch a solution to this puzzle which we think provides an additional argument in support of a gestural-iconic origins scenario for language.